ZX Ferrum #03 27 февраля 2005

Железо

Plans - "The second 'window' - the top box memory address # 8000 - # C000.

  Decided to put an article in this issue. Although the scheme 
is designed me for a long time (that I forget about it, the 
text is lost). Article here some complement and expand.




                    The second window # 8000 - # bfff.


                                      (C) 2003 Dmitry Terentyev


  First, the main thing, why this scheme? Need that is all about
the rest later, and more!

  This development allows access to upper memory
computer (with it any where you installed this development)
not through a window in the address # c000-# ffff, and a range 
of # 8000 - # bfff. That is, as it opens a second window (not 
in vain so named article). 

  What gives? Increasing the speed of programs that do transfer 
from one page in memory to another (due to the fact it is not 
necessary to use lower memory for the buffer, that is about two 
times faster), or if you do not want to touch ordinary 
expansion ports (here, the way we obtain some unification 
standards for memory machines> 128kb, mixing in a single port). 
More For example, in page # 5 to addresses located controller 
that opens the appropriate page in memory and runs the program.


  Closer to the body, so the scheme. It consists of several 
blocks. 



                 Option for the 128 th computer.



                   Multiplexing windows.



                                     LA3 or any inverter

          KP11 v


      14 mux 12 '

  2D0 B1 Q1 ND0 A15 LA3

      September 11 o

  2D1 B2 Q2 ND1 '

       May 7

  2D2 B3 Q3 ND2 o # 80

       April 2 A16

  # 80 B4 Q4 NEW # C0

      13

  OD0 A1 OD0-2 - data port # 7FFD

      10 with the conclusions of TM9

  OD1 A2 2D0-2 - data port # 78FD

       6

  OD2 A3 line with the port # 7FFD to multiplexer (KP11)

       3 cut,

  # C0 A4 in the gap to insert multiplexer KP11


       1 # C0 - an old sample signal # C000

  # 80 S NEW # C0 - a new signal sample # C000

                    apply for entrance to the multiplex KP11

      15 board

         / E the old signal is cut off


                    # 80 - sample signal of the second window

                          addresses # 8000 - # BFFF

     GND



                      Sampling Port # 78FD.


         LA3

                            LL1

                VD1

  A14

          'O>

  A13 1 # 78FD



                VD2

  A12 VD1-VD2 - any diodes

          'O> in case of glitches replace

  A11 on the element LL1



                            blocking the port # 7FFD

  A15

          1

  A10 1

                              'O' o> a new signal

                                              sample

                                              Port # 7FFD

                                              apply instead of

  A9 ^ old

          An old signal

  A8 sample

                       Port # 7FFD



                          Port # 78FD.



          TM8


       April 2

  D0 D0 Q0 2D0

       5 __ 6 2D1 inverted yield

  D1 D1 Q1o 2D1 to resetting the

      October 12 at # 8000 installed

  D2 D2 Q2 2D2 page number 2.

      13 15

         D3 Q3

       9
# 78FD C

       1

         R



    GND



        Option for computers with memory more than 128 kb.



  In the multiplexer the windows to add another chip KP11.


          KP11


      14 mux 12 ND3, ND4, ND5, ND6 match memory

  2D3 D1 Q1 ND3 256, 512, 1024, 2048 kilobytes.

      Sept. 11 signals OD3-OD6 taken from the corresponding
  2D4 D2 Q2 ND4 ing expansion ports (# 1FFD, # DFFD, etc.)

       May 7

  2D5 B3 Q3 ND5

       April 2

  2D6 B4 Q4 ND6

      13

  OD3 A1

      10

  OD4 A2

       6

  OD5 A3

       3

  OD5 A4


       1

  # 80 S


      15

         / E



     GND


  Port # 78FD can do while on the scheme:


          IR23


          reg

   D0 D0 Q1 2D0 any inverter


   D1 D1 Q2 o 2D1


   D2 D2 Q3 2D2


   D3 D3 Q4 2D3


   D4 D4 Q5 2D4


   D5 D5 Q6 2D5


   D6 D6 Q7 2D6


   D7 D7 Q8 2D7

 # 78FD CS


         / E



     GND



  I will explain a little work scheme. When I try to highlight 
the addresses # 8000 - # BFFF Page Number 2, multipleksor KP11 
intercept it and will be printed according to the addresses 
page nomvrom from port # 78FD. 



  Program to check:


  ORG # 6000; <# 8000


  LD HL, # 8000

  LD DE, # C000

  LD BC, # 7FFD

  LD (HL), 0

  LD A, # 16

  OUT (C), A; include at # c000 Page # 6

  LD (DE), A

  AND% 111; transform

  XOR% 010; page number should always Ksor by% 10

                ; Bit1 inverse

  LD B, # 78

  OUT (C), A; include at starnitsu # 8000 # 6

  LD A, (DE)

  CP (HL)

  RET Z; everything is fine, running (a revision)

  RET; not working (not working)